1. Field of the Invention
The present invention relates to a camera system and interchangeable lens having a motion compensation device which shifts a compensation lens to compensate for motion causing blur of an image formed on an image forming plane, such as motion caused by hand shake and the like. More specifically, the present invention relates to a motion compensation device for an optical system which can accurately detect and compensate for motion causing image blur when photographing at close range.
2. Description of the Related Art
Image blur suppression devices are known which suppress, or reduce, blurring of an image formed by an optical system on an image plane. A motion compensation device is a type of image blur suppression device which compensates for motion incident on an optical system. Motion is typically imparted to the optical system by vibrations in the optical system, or in a surrounding holding member. In general, conventional motion compensation devices cause a compensation lens to shift counter to the motion of the optical system so as to shift the image projected by the optical system relative to the optical system.
Conventional cameras use a motion compensation device to suppress image blur resulting from motion of the camera. Such motion is typically caused by hand tremors of the photographer.
For example, Japanese Laid-Open Patent Publication JP-A-H3-46642 discloses a motion compensation device including a first angular velocity sensor to detect the angular velocity around a first axis which is at right angles to the optical axis of a photographic optical system, a second angular velocity sensor to detect the angular velocity around a second axis at right angles to the first axis, a first acceleration sensor to detect acceleration in a first axial direction, a second acceleration sensor to detect acceleration in a second axial direction, a rotational mechanism unit to rotationally drive an optical system around the first and second axes, and a servo circuit to drive control the rotational mechanism unit based on the output signals of the first and second angular velocity sensors and on the output signals of the first and second acceleration sensors.
However, the known motion compensation device can not accurately detect motion causing image blur when photographing at close range in spite of having angular velocity sensors and acceleration sensors to detect motion. As a result of the inability of the conventional motion compensation device to accurately detect motion, a problem occurs in that the motion causing image blur (blurring motion) can not be compensated with high accuracy.